1. Field of the Invention
The present invention relates to a clamping collar comprising a belt carrying first and second tightening lugs, a threaded tightening rod, first and second nuts that co-operate respectively with the first lug and with the second lug and are suitable for co-operating respectively by screw engagement with the tightening rod so as to bring the lugs towards each other in such a manner as to tighten the collar.
2. Description of Related Art
Collars of this type are known, for example, from Documents EP 0 088 507 and GB 2804.
In order to tighten such collars, it is necessary to screw each of the two nuts onto the tightening rod, starting from its first and second ends respectively. Thus, the tightening operation is tedious, because it requires both nuts to be handled in order to tighten both of them on the threaded tightening rod. Ultimately, two end portions of the rod, of substantially equal lengths, extend on either side of the lugs.
Collars exist in which tightening by means of a threaded tightening rod is simplified. For such collars, the threaded tightening rod is a bolt having its head held stationary relative to a lug, so that it is either the head of the bolt or the nut co-operating with the other lug that needs to be screw driven in order to perform the tightening. For example, this is what is shown by Document EP 0 305 232. Although tightening is indeed simplified, those solutions suffer from problems of lack of compactness. At the end of tightening, the head of the bolt is situated against one lug, while the nut is situated against the other lug and the entire bolt portion over which the nut has moved projects beyond the lug with which said nut co-operates. That portion can be long because, in order to mount the collar on the article that is to be tightened, it is necessary for it to have a large diameter initially, which assumes that the length of the rod is relatively substantial.
To summarize, in existing solutions, it is necessary either to handle two nuts, which is tedious, or else to accept poor compactness due to the fact that the entire screwing length of the bolt is situated on one side only of a lug.